I will be there next week and looking forward to it. Driving from Snohomish, Washington. Don't chase em all off before I get there
Here is what I am hearing:
Bear jams are already huge. (I remember when if you went before Memorial Day there were only a few photographers in the park. My how times have changed)
Beryl Springs Sow and two yearlings are out and have been seen near Gibbons Falls
Obsidian Sow and Cub visible fairly regularly until chased by Boar a couple of days back. Has not been seen since.
They have been seeing a sow with cubs fairly regularly near Slough Creek, a different one near Dorothy's turnout in Lamar.
399 and two cubs have been seen in recent days in Teton.
Black Bears in all the normal places between Mammoth and Tower turnoff

Road construction about the same between Norris and Mammoth - best time to navigate nights and weekends

At the moment, it looks like Gardiner (north gate of Yellowstone) will be getting some nice weather from mid May almost to the end of the month. However, the Beartooth Mountains have always gotten a significant amount of rain in May. So my advice is to bring along some warm clothing and some good rain gear for you and your camera gear, just to be safe. I live 60 miles NE of Slough Creek in MT and it's 40 degrees and raining right now. We also have quite of bit of rain and even some snow in the forecast for the next 10 days. So here's my best advice.... pack for ugly weather and if it turns out to be nice while you're in the Park, be happy and count yourself lucky. May and June are, historically, the two wettest months of the year in the GYE. So ya gotta expect some rain. The mountain snow pack is running off right now, so when you're driving in the Park or if you intend to go hiking, be sure to watch closely for any rising river, stream and/or for any falling rocks that have the potential for blocking/washing out roads, camp sites and hiking trails. As a general rule, the Park tries to post a notice at the trail head if the trail is impassible or closed. But you can't always count on that since mountain weather often changes fast and very unexpectedly.

The mountains snowpack was, reportedly, over 120% in March. So the ground is very saturated. In fact, I doubt if the runoff will be completely over until the end of June or early in July. Ditto for the rivers/streams that are in the northern end of the Park. On a cheerier note, the wildlife in the GYE is not only abundant right now, they're also friskier than ever. After such a brutal winter, they must be lovin' the warmer weather, rain and lush vegetation. As for me, I could do without some of that lush vegetation. We'll probably have to mow our 5 acres of meadow grass at least 4 times before we even go to the Park in mid June. Argh...

First day spent in Tetons Friday 11th. Happy to see Blondie showing off her beautiful cubs along the road close to start of road up to Pilgrim creek. After that two mooses by and in the river by bridge between Dornans/Visitor center.

Saturday 12th:
Based in West Y for a couple of days. Since going up to Mammoth for 5 days later on we focused on Madison/Norris/road up towards Mammoth turning at road construction/Canyon/ Hayden/Fishing bridge to Lake Butte overlook.
Not much to see apart from:
Lots of beautiful harlequin ducks at Le Hardy Rapids and some ancient leftovers of a bison carcass(head) hence the bear warning sign by the stairs.
Coyotes at 2 different areas along Madison River where there are swamps/river on right side driving into the park from West Y.
Red fox appeared a few hundred meters before entrance exit on my way out of the park at west gate. Saw it a few meters behind my car in my rear view mirror. Kind of difficult to take photos when that happens. I guess I was outfoxed.

Heading up to Lamar and Northern Range today expecting much more than yesterday. Fingers crossed.